INACTIVATION AND MUTATION INDUCTION TO 6-THIOGUANINE RESISTANCE IN V79 HAMSTER FIBROBLASTS BY SIMULATED SUNLIGHT

Abstract— Risk estimates for an enhancement of ultraviolet radiation are frequently based on action spectra, in which case it is assumed that the different components of natural or artificial sunlight act independently and the overall effect can be derived by a simple summation procedure. Such an approach, however, may not always be justified and-as shown earlier-lead to a considerable underestimation of inactivation and mutation induction to 6-thioguanine resistance by filtered 'sunlamp'-radiation. Here we report on experiments employing different kinds of simulated sunlight. A good agreement between theoretical and experimental results was found. The apparent contradiction can be resolved by an analysis for the spectral regions primarily responsible for the overall effect.